Abstract
In the preceding paper, the authors analysed mechanism of flow of Bingham plastic materials through a screw extruder, which has a uniform channel. And equations of flow rate under various conditions were obtained in convenient forms as the function of three nondimensional terms, w, z and U. The experimental data were in good agreement with the theoretical results. In this paper, the results of preceding study were developed so as to be applicable to a variable depth type extruder, of which the height of screw thread is a linear function of helical length of the channel. Extruder of this type is often called compression type, and it is frequently used in various chemical industry for the purpose of increasing its ability of compressing and kneading pla stic materials. The results of study obtained are as follows. When the gradient of depth of the screw channel is very small, the pressure distribution along the channel is given by: for the range, for the range, where, H1 and H2 are respectively the depth of channel at the inlet and outlet port. For the rangeorthe relation between p and H is very difficult to obtain with precision, but by the aid of equations 13), 15), and non-dimensional term n, it was successfully correlated. These results are shown by curves in Fig. 6. Equations 13), 15) and Fig. 6 are very important in and convenient for designing purpose. So an example of how to solve design problems was given for the purpose of showing concretely the results obtained.